1. Field of the Invention
The present invention relates to an auxiliary handle for a hand-held power tool such as a power drill, a hammer drill or a chisel hammer and includes a clamping section for securing the auxiliary handle on a section of the power tool, a gripping member for holding the auxiliary handle, a lockable lag hinge provided between the attachment section and the gripping member and having a pivot pin, a tensioning member for tightening and loosening the clamping section and arranged on an end of the pivot pin of the lag hinge, and a locking device for locking and releasing the lag hinge.
2. Description of the Prior Art
In power tools, auxiliary handles of the type described above are provided, if needed, in form of a side handle mounted, e.g., on a housing section adjacent to a tool holder for guiding the power tool. It is known to form a gripping member of the auxiliary handle pivotable about a pivot axis in order to optimally guide the power tool and to enable different gripping positions of the auxiliary handle on the power tool, which would insure a less tiring operation. A lag hinge provides for a pivotal movement of the gripping member relative to the attachment section of the auxiliary handle. The pivoting of the gripping member permits to adjust the gravity point of the power tool with respect to the tool user. Often, the gripping member is adjusted during the power tool use.
In order to prevent an inadvertent re-adjustment of the gripping member of the auxiliary handle in a locking position of the lag hinge, there are usually provided, e.g., between the clamping section and the gripping member, engageable in each other, toothings. For pivoting of the gripping member, this engagement should be broken and then again re-established. This occupies an increased amount of time.
German Publication DE 10 2006 055 524 A1 discloses an auxiliary handle for a hand-held power tool and having its clamping section formed as a clamping sleeve for mounting the auxiliary handle on a section of the power tool. The auxiliary handle also includes a gripping member for grasping and holding the auxiliary handle. Between the clamping section and the gripping member, a lockable lag hinge is arranged. The lag hinge has a pivot pin a longitudinal axis of which forms the pivot axis of the lag hinge. Further, there is provided an actuation knob that forms a locking member and is arranged on an end of the pivot pin, being secured on a section of the pivot pin provided with an outer thread. Between the tensioning member and a section of the gripping member, there is provide a cone-shaped, elastically deformable engagement member frictionally engageable in a conically widening recessed opening formed in a section of the gripping member. Between the gripping member and the clamping section, toothings are provided which form a locking device and which lock the lag hinge when formlockingly engaging each other, and release the lag hinge in their disengaged position.
With such design of the auxiliary handle, the required number of revolutions of the locking member for locking and releasing the lag hinge and for tightening and loosening the clamping section is reduced.
The drawback of the above-described auxiliary handle consists in that for releasing the lag hinge, the engaging each other, elements of the locking device should be spaced from each other by at least the height of the teeth so that the gripping member can be pivoted relative to the clamping section. This can lead to loosening of the tightening of the clamping section and thereby adversely affect its fixation on the power tool, so that the auxiliary handle can automatically pivot about an operational axis defined by a working tool. Therefore, with a new locking of the lag hinge, additionally, a proper orientation of the entire auxiliary handle relative to the power tool should be carefully readjusted.
Accordingly, an object of the present invention is an auxiliary handle for a hand-held power tool in which the above-discussed drawbacks of a known auxiliary handle are eliminated.
Another object of the present invention is an auxiliary handle for a hand-held power tool and that would enable a simple and rapid pivoting of the gripping member, without affecting the tightening of the clamping section.